A communication network includes a plurality of mobile devices, a plurality of Base Transceiver Stations (BTSs), and at least one Base Station Controller (BSC). Examples of mobile devices include cell phones, Personal Digital Assistants (PDAs), etc. In the downlink, the BSC generates requests for resources to transmit data to the mobile, and, in the uplink, the mobile devices generate the requests for resources to transmit data. The requests are sent to the BTSs, which may schedule the requests.
The request may be scheduled using a variety of methods including the weighted fair queuing method, the earliest-due-date method, the priority-queuing method and the shortest fair queuing method. In the shortest fair queuing method, each request is stamped with a start tag based on a pre-determined criteria. The requests are then served in an increasing order of the start tags associated with each request.
The BTSs may schedule the requests from the mobile devices in a First In First Out (FIFO) order. A request received first by the BTS may be given a higher priority for allocation of the resource than a request received later.
Alternately, the BTSs may schedule the requests in a non-FIFO order, such as based on a priority of the request. The priority of the request is determined by using one or more predetermined criteria. The BTSs receive the requests at different times and have to wait for a predetermined period so as to receive all requests for a time slice before scheduling these requests for the time slice. Thereafter, sorting is performed and the requests are scheduled and served in the next time slice.
One or more of the methods described above may suffer from one or more of the following limitations. Firstly, they do not operate in a distributed soft handoff environment. Secondly, the requests served in the FIFO order do not take into account the priorities associated with the requests. Thirdly, for serving requests in the non-FIFO order the BTSs have to wait till a predetermined period of time to receive each request. Moreover, in a Soft Hand Off (SHO) environment, resources that have been allocated cannot be reallocated if they are greater than the final allocation for a mobile device. Lastly, the requests served in a non-FIFO order require high processing on the communication network.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.